This invention relates to a sampling system and method and more particularly, this invention relates to an automatic sampling system and method which is advantageously used in collecting samples in sample containers with a substantially zero head space.
It is known to use sampling apparatuses in applications such as waste treatment, stream monitoring, pollution abatement, industrial effluent control, water management studies, and environmental law enforcement. Waste water streams, for example, have to be checked periodically to seen if the streams meet with current standards for clean water controls and therefore sampling of the streams must be obtained to analyze such sample in order to check that the streams are in compliance with the regulations regarding the environment.
For example, in sampling waste water streams, the Environmental Protection Agency (EPA) requires that a volume of sample of a waste water stream be collected at four evenly spaced intervals over a twenty-four hour period (every six hours). Each of the four sample volumes must be collected in individual containers and all headspace (air gap) in the containers must be eliminated. Elimination of air gap from the container is important because air in the sample container can cause inaccurate analysis of the components of interest in the collected sample. This sampling required by the EPA is usually done manually by grab samples. However, with grab sampling uniform sampling is usually not carried out because sampling techniques of individuals can vary from individual to individual. Usually an air space is collected in the sample container using manual grab samples.
An alternative to grab samples is an automatic sampling system. An automatic sampling system would save an operator's time and cost in obtaining the required samples, particularly when samples are required at, for example, six hour intervals every twenty-four hours.
There are known automatic liquid samplers which use positive sample recovery. However, a positive sample recovery type automatic liquid sampler does not adequately eliminate all of the head space in a sample collection container during operation. Therefore, such sampler would not satisfactorily comply with the EPA's requirements of collecting samples as discussed above.
It would be desirous to provide an automatic sampling system and procedure to collect samples in containers with a zero headspace.